Approaches to optimizing the burnup depth using radial fuel rod profiling

This paper raises the question of the optimal use of resources in the process of nuclear fuel burnup. Optimization tasks boil down to a possible reduction in the resources used while maintaining the current characteristics or extending the campaign by using the same amount of resources. As a solution to the simulated problems, profiling of fuel pellets with a burnable absorber is proposed. Profiling is carried out in proportion to the radial burnup of the fuel rod relative to the average value. The use of this technology in standard fuel assemblies is of interest from the standpoint of ensuring safety and improving technical and economic characteristics. The calculations were carried out in the Serpent software package, which performs precision neutron-physical calculations by the Monte Carlo method. Compared to a standard assembly, the increase in keff in the middle of the fuel campaign provides more flexibility during the operation of the reactor plant in the moments before refueling. Profiling had no effect on the length of the fuel campaign. The impact on reactor campaigns allows us to conclude that the technology can be used to optimize fuel enrichment and extend the fuel campaign or reduce the use of a given boric acid concentration at the beginning of the campaign.